The present invention relates generally to a roof-mounted snow guard assembly to retain accumulated snow and prevent damage and injury caused by snow sliding off the roof surface, and more particularly, to an improved mounting block for securing such snow guard assemblies to a metal roof seam.
Snow guard assemblies have long been used for inhibiting and directing the movement of snow and ice across selected or pitched areas of roofs, as a preventive measure to mitigate the damage caused by migrating and falling snow and ice accumulations. An early application of snow guard assemblies is taught in U.S. Pat. No. 42,972 to Howe, which issued May 31, 1864. Recently, snow guard assemblies have increased in popularity, and currently several snow guard mounting assemblies serve to hold snowloads on roofs. Relevant examples include U.S. Pat. Nos. 5,613,328, and 5,732,513, each to Alley, each of which is herein incorporated in its entirety by reference.
Changing weather conditions, such as high winds or cyclically varying temperatures, create an environment which can induce physical changes in the accumulated snow, and give rise to the conditions tending to cause a snowpack to slide off of a sloped roof. Dislocated snow and ice often cause damage to surrounding property and, in some cases, the sliding snow can cause serious bodily injury. The problem of sliding snow is particularly prevalent on metal roofs. Metal roofs offer many structural advantages, such as strength and durability. However, because metal tends to absorb environmental heat, even a minimal amount of panel expansion or contraction exacerbates the conditions leading to snow slides. Furthermore, metal roofs generally afford little surface friction, which is also conducive to snow slides.
The increasing popularity of construction incorporating metal roof materials also poses particular problems with respect to attaching snow guard assemblies. A typical metal roof comprises a plurality of juxtaposed metal panels typically having substantially perpendicular edges that abut to form a joint therebetween. The perpendicular edges of the abutting panels are each crimped together and/or bent downwardly over each other forming a sealed seam which both connects the roofing panels and prevents fluid communication between and beneath the roof panels.
In snow guard assemblies for seamed metal roofs, the mounting block assembly is typically secured to the roof seam using a coupling means, such as screws or bolts. These screws or bolts generally pass through a sidewall of the mounting block seated around the seam, and extend inwardly, to contact the roof seam. However, screws and bolts tend to puncture, abrade, or otherwise damage the surface coating of the metal roof seam seal when tightened to securely fasten the mounting assembly. Holes or fissures thusly created destroy the hermeticity of the metal roof, especially upon removal of the snow guard, and allow water to permeate the seam even while the snow guard is still attached. The water tends to attack the exposed metal beneath the damaged surface coating, creating rust or seeping rust stains, which weakens the metal and diminishes the intrinsic aesthetic qualities of metal roofs.
Prior attempts to address this problem include using a mounting block capable of being attached to a metal roof without tearing, puncturing or otherwise destroying the hermeticity of the metal roof seam, as described U.S. Pat. No. 5,613,328. In order to attach the mounting block to the seam, a ball and set-screw is provided, such that the curved surface of the ball, rather than the end of the screw, engages a portion of the roof seam. As the screw is tightened to attach the mounting block, the ball forms a pocket in the engaged portion of the seam such that the mounting block can be secured to the roof without piercing or tearing the seam.
Although this method of attachment is an improvement over the prior art attaching means, drawbacks remain. For example, the entire holding force per coupling means is limited to the contact area between the seam and each ball, which is only a singular, independent contact surface. Because such a design requires that the entire contact force be applied through a single contact surface on each ball, the total amount of static holding force (which is equal to the summation of the holding forces of each individual contact surface) is determined by the number of balls engaging the roof seam. Thus, the net holding force available for holding the mounting block in place is significantly limited, and sliding will occur if the force of the snow load exceeds the friction force at that singular point of contact.
Yet another drawback of the ball and set-screw assembly relates to the occasional rotation of the ball element in conjunction with the turning of the set-screw, instead of gripping to form a stationary contact surface with the metal seam. This unwanted turning may give rise to damage on the contact surface of the seam, and effectively undermine the benefits of employing a ball and set-screw coupling means.
Another drawback associated with prior art mounting block assemblies for snow guard assemblies relates to corrosion caused by the contact between the metal seam and the metal groove in the mounting block coupled with the exposure to high degrees of moisture typical of roofs. The corrosion is a result of a galvanic reaction between the metal roof, typically copper, and the metal groove in the mounting block, typically aluminum. This can lead to many harmful conditions, both cosmetic and structural, including unsightly deposits on the roof panels and a weakened coupling between the seam and snow guard assembly. Additionally, the corrosion and moisture infiltration eventually degrade the hermeticity of the metal roof.
Efforts to combat the corrosion caused by the galvanic reaction include fabricating the mounting block using a non-reactive metal, such as stainless steel. However, using stainless steel instead of aluminum significantly increases overall manufacturing and consumer costs, and does not address the problem of moisture communication and physical harm to the surface of the seam caused by fastening with screws or bolts. Another attempt to combat reactivity involves using a non-corrosive insert as an interface in the metal groove of the mounting block, between the mounting block and the roof seam, as described in Applicant""s pending application Ser. No. 09/397,938, the entirety of which is incorporated herein by reference. However, such non-reactive inserts do not afford the seam protection from invasive coupling means, since the coupling means penetrate the inserts and directly contact the seam.
Thus, it would be desirable to provide a snow guard assembly having a means for securing a mounting block assembly onto a metal roof seam which addresses each of the primary problems associated with the prior art. That is, it would be desirable to provide a snow guard assembly having a means for securing a mounting block assembly onto a metal roof seam which prevents physical breach of the seam integrity by a coupling means and which preferably eliminates the negative effects of galvanic reactions between the roofing material and the mounting block, to better preserve the hermeticity of the roof. Further, a cost effective means of achieving the aforementioned goals is also desired.
It is an object of the present invention to overcome the drawbacks of the prior art, particularly to provide a cost effective snow guard assembly having a means for securing a mounting block assembly onto a metal roof seam which prevents physical breach of the seam integrity by a coupling means and which preferably eliminates the negative effects of galvanic reactions between the roofing material and the mounting block.
In accordance with one embodiment of the present invention, a snow guard assembly adapted to be attached to a metal roof seam by a mounting assembly is provided. The mounting assembly includes a mounting block having a seam-receiving groove formed in a bottom surface thereof, and at least one coupling means extending through a first side portion of the mounting block and having a terminal end adapted to move toward a central axis of the seam-receiving groove. The assembly further includes at least one clamping member, interposed between the central axis of the seam-receiving groove and the coupling means, having a first side opposing the terminal end of the coupling means and a second side adapted to oppose a metal roof seam. The clamping member is preferably a plastically deformable metal material having a thickness that is sufficiently small such that, upon engagement of the terminal end of the coupling means on the first side of the clamping member, a protrusion is formed on the second side of the clamping member at a location opposed to the terminal end of the coupling means.
Preferably, the clamping member is an integral part of the mounting block, the seam-receiving groove is defined partially by an internal upper surface of the mounting block, and the clamping member extends downwardly from the internal upper surface. It is also preferable that the terminal end of the coupling means passes through a first internal side surface of the mounting block and a second internal side surface of the mounting block includes one of a recess and a protrusion at a location opposed to the terminal end of the coupling means. It is also preferred to include at least two of the coupling means extending through the first side portion of the mounting block, each coupling means being adapted to engage different portions of the clamping member. Further, the seam-receiving groove preferably extends along the entire length of the mounting block and the clamping member extends along the entire length of the seam-receiving groove.
According to a second embodiment of the present invention, the snow guard assembly includes a mounting assembly having a mounting block having a seam-receiving groove formed in a bottom surface thereof, defined partially by an internal upper surface of the mounting block. The mounting block also includes first and second coupling means extending through opposed first and second side portions of the mounting block, respectively. Each coupling means includes a terminal end adapted to move toward a central axis of the seam-receiving groove. The mounting assembly further includes first and second clamping members formed integrally with the mounting block, extending downwardly from the internal upper surface, and interposed between the central axis of the seam-receiving groove and the first and second coupling means respectively. Each clamping member includes a first side opposing the terminal end of a respective one of the coupling means and a second side adapted to oppose a metal roof seam. Each clamping member is made of a plastically deformable metal material having a thickness that is sufficiently small such that, upon engagement of the terminal end of a respective one of the coupling means on the first side of the clamping member, a protrusion is formed on the second side of the clamping member at a location opposed to the terminal end of the respective one of the coupling means. The seam-receiving groove of the second embodiment preferably extends along the entire length of the mounting block, and the first and second clamping members extend along the entire length of the seam-receiving groove in a spaced parallel relationship with one another on opposing sides of the central axis of the seam-receiving groove. The first and second coupling means are preferably axially offset from one another along the length of the mounting block.
In a preferred modification of the second embodiment, the second side of each of the first and second clamping members preferably includes a corrosion-resistant, non-metallic coating. More preferably, the corrosion-resistant, non-metallic coating also covers that portion of the internal upper surface of the mounting block that is positioned between the first and second clamping members.
According to a third embodiment of the present invention, the snow guard assembly includes a mounting assembly having a mounting block having a seam-receiving groove formed in a bottom surface thereof, defined partially by an internal upper surface of the mounting block. The mounting assembly also includes first and second coupling means extending through opposed first and second side portions of the mounting block, respectively, wherein each coupling means includes a terminal end adapted to move toward a central axis of the seam-receiving groove. The mounting assembly further includes a clamping member having first and second sidewalls spaced apart from one another. The clamping member is freely positioned within the seam-receiving groove such that the first and second sidewalls are positioned between the central axis of the seam-receiving groove and the first and second coupling means, respectively. Each of the sidewalls includes a first side opposing the terminal end of a respective one of the coupling means and a second side adapted to oppose a metal roof seam.
The sidewalls of the clamping member are preferably made of a plastically deformable metal material having a thickness that is sufficiently small such that, upon engagement of the terminal end of a respective one of the coupling means on the first side of the sidewall, a protrusion is formed on the second side of the sidewall at a location opposed to the terminal end of the respective one of the coupling means.
The preferred clamping member of the third embodiment also includes a top wall connecting the first and second sidewalls to one another. More preferably, the clamping member is configured in the shape of an inverted U, including a non-metallic coating on the second side of each sidewall of the clamping member. It is further preferred that the corrosion-resistant, non-metallic coating also covers an internal surface of the top wall of the clamping member. It is also preferred that the mounting assembly includes two clamping members spaced apart from one another along the length of the mounting block, wherein the first and second coupling means engage a first one of the clamping members, and the first and second coupling means are axially offset from one another along the length of the mounting block. Third and fourth coupling means, extending through the opposed first and second side portions of the mounting block, respectively, can also be provided. Each of the third and fourth coupling means includes a terminal end that engages the other one of the clamping members. The third and fourth coupling means are also axially offset from one another along the length of the mounting block.
According to another embodiment of the present invention, a coupling element adaptable to connect a first and a second component is provided, including a substantially cylindrical first member adapted to contact a first component, and a second member adapted to contact the first member and a second component. The first member extends in a longitudinal direction from a first end thereof to an opposed second end thereof. The first member includes a bore portion extending in the longitudinal direction from an opening on the second end of the first member toward the first end of the first member, and having a circumference C. The second member includes a substantially cylindrical first portion having a first end, an opposed second end, and a circumference C1 being less than C. The second member further includes a second portion proximate the second end of the first portion, having a dimension extending in a direction substantially perpendicular to the longitudinal direction, and having a first surface from which the first portion extends in a longitudinal direction and an opposed second surface adapted to contact a second component.